Rail flaw detector mechanism



H c. DRAKE 2,163,424

RAIL FLAW DETECTOR MECHANISM June 20, 1939.

Filed Dec. 51, 1935 \NVENTOR 13 Hal-marl C. flrake Patented June 20, 1939 STATES RAIL FLAW DETECTOR MECHANISM Harcourt 0. Brake, Hemps tead, N, Y., assignor to Sperry Products, Inc., Brookilyn, N. Y., a corporation of New York Application December 31, 1935, Serial No. 56,978

22 Claims. (or 175-183) This invention relates to rail fissure detector cars of the type now well known as the Sperry rail flaw detector. These cars operate upon the principle of sending current through the rail to establish an electromagnetic field surrounding the same and detecting variations in said field caused by the presence of flaws by means of detector mechanism in the form of opposed induction coils which normally cut a constant number of lines of force but which cut a different number of lines of force on entering a region of ,fiaw. The E. M. F. thus induced is amplified and caused to operate an indicator such as a recorder. The method of energizing the rail consists in utilizing spaced sets of current brushes, the detector mechanism being positioned between the front and rear sets of brushes.

It has been found that if the current has a chance to pass through the rail well in advance of the detector means, much better results are obtained due, no doubt, to the fact that the longer the interval which elapses between the passing of the front current brushes over a given point and the passage of the detector means over the same point, the more homogeneous will be the alignment of the molecules which previously were arranged in heterogeneous fashion. For this reason, applicant in his Patent No. 1,944,930, granted Jan, 30, 1934, disclosed a method of preenergizing the rail by utilizing a third set of brushes in advance of the ordinary sets of front and rear brushes on either side of the detecting means. Somewhat the same effect of preenergization can be obtained without the utilization of a third set of brushes by increasing the distance between the front and rear sets of brushes and particularly by increasing the distance of the front set of brushes from the detector means. This system, however, presents diificulties, as will be more fully explained in the specification below in conjunction with the illustrations, by reason of the fact that when the front brushes pass a bad rail joint or an insulated rail joint, current no longer flows through the rail and that portion of the rail contained between the front brushes and the search unit either remains untested or has to be tested by hand.

It is the object of the present invention to provide an arrangement whereby a substantial degree of preenergization may be obtained by the use of the two ordinary sets of brushes and at the same time avoid the possibility of failure to test portions of the rail adjacent bad joints or insulated joints.

Other objects and advantages of this invention will-become apparent in the following detailed description thereof.

In the accompanying drawing,

Figured is a side elevation of a portion of a rail fissure detector car showing my invention 5 applied thereto.

Figures 2 and 3 are diagrammatic views illustrating the operation of the manual form of my invention.

Figures 4 and 5 are diagrammatic views il1us-' trating the operation of the automatic form of my invention.

Figure 6 is a diagram showing a modification of the Figures 2 and 3 form of the invention.

Figure 7 is a wiring diagram showing a modification of the Figures 4 and 5 form of the invention.

Referring to Fig. 1 of the drawing, there is disclosed the essential elements of the Sperry rail fissure detector car which consists of a car body 20 it, only a portion of which is shown, mounted for movement along the rails R, and supporting thereon the rail fissure detector mechanism. Said mechanism is supported on a current brush carriage 02 which supports sets of front and rear current brushes i3 and Hi to which current is supplied from a generator G within the car. The said current brush carriage i2 is normally held in elevated position by means of cables i5 and springs, not shown, butmay be lowered into 0 engagement with the rail by passing compressed fiuid into cylinders ill to depress pistons therein and hence depress piston rods it pivotally connected to said current brush carriage to lower the sameagainst the action of the restoring springs. The said carriage may be provided with flanged wheels is adapted to engage the rails and guide the carriage along the rail in fixed relation thereto. Current passing between the front and rear brushes i3 and M when the carriage engages the rail sets up an electromagnetic field which will be uniform except in the region of fiaw, where it will be distorted. Such variations in the electromagnetic field may be detected by means of one or more pairs of induction .coils 2i con- 45 tained in a housing 22 supported on a detector carriage 23 which rides upon the rail by means such as wheels 26. The housing 22 with the detector coils is held in fixed relation to the rail at a constant distance above the surface thereof. The detector carriage 23 is supported on the current brush carriage 82 by means of loosely fitting bolts 26 and spring 25. The coils are arranged in opposed relation so that any change in current supply will not generate a differential E. M. F. because such change affects these coils equally and oppositely. When, however, a region of flaw is encountered, first one coil and then the other will enter the said region of flaw to cut a different number of lines of force from that which it normally cuts, and this generates an E. M. F. which after being amplified may be caused to operate any suitable indicator, such as a recorder.

As stated in the introduction to this specification, it is desirable to obtain the maximum degree of preenergization before the detector coils pass over any given point of the rail, and for this reason the front brushes l3 are shown spaced a substantial distance from the detector housing 22, and the rear brushes I4 are shown as spaced an equal distance from said housing although, as will be described fully in a modified form of the invention, the rear brushes may be positioned nearer to the detector housing 22. As the car moves along the rail it will be seen that current enters the rail at a point substantially in advance of the detector coils, and thus each point of the rail over which the detector coils pass will have been subjected to the action of the current for a substantial period before the detector coils reach the said point. Thus the molecules will have had a chance to arrange themselves in homogeneous relation, and experience shows that better testing results will be obtained. The front brushes l3 may be positioned as much as ten feet in advance of the detector coils and the rear brushes 14 may be positioned a similar distance therefrom.

The above described arrangement will yield the advantageous result of preenergization without disadvantageous consequences, so long as the rail joints are in gOOd condition to offer low resistance to the passage of the current, in which case the mere fact that the brushes l3 have passed a joint J will not affect the efiiciency of the testing since current will pass from the next rail through the joint J and permit the full electromagnetic field to be maintained around the rail. If, however, there are rail joints which are poorly made so that they offer substantial resistance to the passage of current, or if the joint is an insulated joint such as occurs at intervals along most tracks, then it will be seen that as soon as front brushes [3 pass beyond joint J the current through the rail which is being tested by the detector coils will fall off, or be entirely eliminated, so that testing will be impossible; and since the front brushes ii are ten feet from the detector coil, it means that the last ten feet of rail which the coils 2! are testing cannot be tested by the regular testing operation and will either remain untested. or must be tested by hand, which is a time-consuming and tedious operation. Similarly, the first part of the succeeding rail will be without testing since insufficient current will pass into the succeeding rail until the rear brushes i4 have passed the joint J, and since the distance from front to rear brushes is as much as twenty feet, the first twenty feet of the succeeding rail will be without testing or else will have to be handtested.

I provide means whereby the above disadvantageous consequences of securing preenergization by increasing the distance of the brushes from the detector unit may be avoided. I provide below for two cases, the first for use on railroads where the joints are in good condition so that substantially all of the current may pass therethrough and provision must be made only for insulated joints; and the second for use on railroads where the joints are in poor condition so that not only at insulated but at all ordinary joints the current would ordinarily be cut off completely or substantially.

The first of these forms, namely, the type to be used on railroads where the joints are good and only the case of insulated joints requires special attention, is shown diagrammatically in Figs. 2 and 3. In this form, an auxiliary set of front brushes l3 and an auxiliary set of rear brushes 14' are provided positioned closely adjacent to the detector coils 2 I. The circuit from generator G normally passes through brushes l3 and I4 but when the operator at the front of the car sees an insulated joint approaching, he operates switches S and S to close sets of contacts and 30 to establish a shunt circuit from generator G through auxiliary brushes I3 and I4. This will permit testing close to the joint J by reason of the close positioning of the brushes I3 and I4 tu the housing 22. As soon as the rear brushes [4 have passed the insulated joint the operator opens the switches S and S to reestablish the circuit through brushes I 3 and [4. In other words, for the brief period in advance of and following an insulated joint, the advantages of preenergization will not be obtained but testing will be possible to a point closely adjacent the joint J.

If desired, the form shown in Fig. 6 may be employed wherein the rear brushes l4 are normally positioned closely adjacent the housing 22 and therefore only an auxiliary set of front brushes l3 need be employed with a single switch S to be closed by the operator on approaching an insulated joint.

In Figs. 4 and 5, I have disclosed a form of my invention which is adapted for use on roads wherein the joints are poorly constructed and offer high resistance to the passage of current. In this form of the invention, I provide for automatic shifting from main brushes I3 and I4 positioned at a relatively large distance from the housing, to an auxiliary set of brushes l3, l4 positioned relatively close to the said housing. For this purpose, I have mounted on the current brush carriage l2 a pair of non-magnetic joint fingers 40 and 40 which are adapted to slide along the gage side of the rail and engage the angle bar B which unites the rails at a joint. As the front joint finger 4i] strikes the angle bar B it swings about its pivot 45 to open a set of contacts 42 and close a set of contacts 43 to break the circuit from generator G through brushes l3 and establish a circuit through auxiliary brushes l3. finger 40 has an extension 4i designed to maintain engagement with angle bar B until the rear finger 40' engages said angle bar. The fingers 46 and 40 are connected by a link 50 so that they are actuated together. When finger 40 is turned about its pivot 45 by engagement with angle bar B to open contacts 42 and close contacts 43 to establish a circuit from auxiliary brushes i3, finger 40 is moved around its pivot 46 to open contacts 41 and close contacts 48 to establish the circuit from generator G through auxiliary brushes M. The joint finger 40' will remain in engagement with angle bar B to maintain the circuit through auxiliary brush l4 until the main brush M has passed beyond the joint. At this point, finger 40 leaves the angle bar and permits the circuit to be reestablished through brushes l3 and I4.

As shown in Fig. 7, the rear brushes [4 may be The.

permanently positioned close'to the housingv 22, I through said rail in the same direction as said in which case only one set of auxiliary brushes l3 need be employed and only one joint finger 40, which will maintain the auxiliary circuit from generator G through brushes l3 and brushes ll until the said brushes [4 have passed beyond the joint, whereupon the joint finger 40 will pass beyond the angle bar to permit reestablishment of the circuit through brushes l3 and H.

In accordance with the provlsionsof the patent statutes, I have herein described the principle and operation of my invention, together with the apparatus which I now consider to represent the best embodiment thereof, but I desire to have it understood that the apparatus shown is only illustrative and that the invention can be carried out by other equivalent means. Also, while it is designed to use the various features and elements in the combination and relations described, some of these may be altered and others omitted without interfering with the more general results outlined, and the invention extends to such use.

Having described my invention, what I claim and desire to secure by Letters Patent is:

1. In a detector mechanism adapted to travel along the rails of a track for detecting flaws therein, a source of current, means for establishing a main circuit from said source through said rail, means for establishing an auxiliary circuit independent of said main circuit from said source through said rail in the same direction as said main circuit, and a detector unit, one of said circuits being arranged so that current enters said rail closer to said unit than current from the other circuit.

2. In a detector mechanism adapted to travel along the rails of a track for detecting flaws therein, a source of current, means for establishing a main circuit from said source through said rail, means for establishing an auxiliary circuit independent of said main circuit from said source through said rail in the same direction as said main circuit, and a detector unit, said auxiliary circuit being arranged so that current enters said rail closer to said unit than current from said main circuit.

3. In a detector mechanism adapted to travel along the rails of a track for detecting flaws therein, a source of current, means for establishing a main circuit from said source through .said rail, means for establishing an auxiliary circuit from said source through said rail, a detector unit, one of said circuits being arranged so that current enters said rail closer to said unit than current from the other circuit. and means whereby either of said circuits may be rendered effective and the other circuit rendered ineffective.

4. In a detector mechanism adapted to travel along the rails of a track for detecting flaws therein, a source of current, means for establishing a main circuit from said source through said rail, means for establishing an auxiliary circuit from said source through said rail, a detector unit, said auxiliary circuit being arranged so that current enters said rail closer to said unitthan current from said main circuit, and means whereby either of said circuits may be rendered effective and the other circuit rendered ineffective.

5. In a detector mechanism adapted to travel along the rails of a track for detecting flaws therein, a source of current, means for establishing a main circuit from said source through said rail, means for establishing an auxiliary circuit independent of said main circuit from said source main circuit, and a detector unit, each of said spaced closer to said unit than the brushes of the other set.

6.. In-;a detectormechanism, adapted to. travel therein, a source of current, means for establishinga main circuit from'said source through along the rails of a track for detecting-flaws said rail, means for establishing an auxiliary circuit independent-0f said main circuit from said source through said rail ins-the, same, direction as said main circuit, and a detector unit, each of said circuits including, a set of brushes engaging the .rail, said unit being positioned between the brushesof each set, the brushes of said auxiliary circuit being spaced closer to said unit than the brushes of said main circuit.

'7. In a detector mechanism adapted to travel along the rails of a track for detecting flaws therein, a source of current, means for establishing a main circuit from said source through said rail, means for establishing an auxiliary circuit from said source through said rail, and a detector unit, said main circuit including a set of brushes engaging the rail, said unit being positioned between said brushes and closer to the rear brush than the front brush, said auxiliary. circuit including said rear brush and an additional front brush positioned nearer to said unit than said first front brush.

8. In a detector mechanism adapted to travel along the rails of a track for detecting flaws therein, a source of current, means for establishing a main circuit from said source through said rail, means for establishing an auxiliary circuit from said source through said rail, a detector unit, each of said circuits including a set of brushes engaging the rail, said unit being positioned between the brushes of each set, the brushes of one set being spaced closer to said unit than the brushes of the other set, and means whereby either of said circuits may be rendered effective and the other circuit rendered inefiective.

9. In a detector mechanism adapted to travel along the rails of a track for detecting flaws therein, a source of current, means for establish ing a main circuit from said source through said rail, means for establishing an auxiliary circuit from said source through said rail, a detector unit, each of said circuits including a set of brushes engaging the rail, said unit being positioned between the brushes of each set, the brushes of said auxiliary circuit being spaced closer to said unit than the brushes of said main circuit, and means whereby either of said circuits may be rendered effective and the other circuit rendered ineffective.

10. In a detector mechanism adapted to travel along the rails of a track for detecting flaws therein, a source of current, means for establishing a main circuit from said source through said rail, means for establishing an auxiliary circuit from saidsource through said rail, a detector unit, said main circuit including a set of brush es engaging'the rail, said unit being positioned between said brushes and closer to the rear brush than the front brush, said auxiliary circuit including said rear brush and an additional front brush positioned nearer to said unit than said other circuit rendered ineffective,

11. In a detector mechanism adapted to travel along the rails of a track for detecting flaws therein, said rails having joints, a source of current, means for establishing a main circuit from said source through said rail, means for establishing an auxiliary circuit from said source through said rail, a detector unit, one of said circuits being arranged so that current enters said rail closer to said unit than current from the other circuit, means responsiveto said rail joints and means whereby said rail-jointresponsive means renders one of said circuits effective and the other circuit ineffective.

12. In a detector mechanism adapted to travel along the rails of a track for detecting flaws therein, said rails having joints, a source of current, means for establishing a main circuit from said source through said rail, means for establishing an auxiliary circuit from said source through said rail, a detector unit, one of said circuits being arranged so that current enters said rail close-r to said unit than current from the other circuit, means normally maintaining said main circuit effective, means responsive to said rail joints, and means whereby said rail-jointresponsive means renders said main circuit ineffective and said auxiliary circuit efiective.

13. In a detector mechanism adapted to travel along the rails of a track for detecting flaws therein, said rails having joints including angle bars, a source of current, means for establishing a main circuit from said source through said rail, means for establishing an auxiliary circuit from said source through said rail, a detector unit, one of said circuits being arranged so that current enters said rail closer to said unit than current from the other circuit, means adapted to engage said angle bars, and means whereby the engagement of said preceding means with said angle bars renders one of said circuits effective and the other circuit ineffective.

14. In a detector mechanism adapted to travel along the rails of a track for detecting flaws therein, said rails having'joints including angle bars, a source of current, means for establishing a main circuit from said source through said rail, means for establishing an auxiliary circuit from said source through said rail, a detector unit, said auxiliary circuit being arranged so that current enters said rail closer to said unit than current from said main circuit, means adapted to engage said angle bars, and means whereby the engagement of said preceding means with said angle bars renders said main circuit ineffective and said auxiliary circuit efiective.

15. In a detector mechanism adapted to travel along the rails of a track for detecting flaws therein, said rails having joints, a source of current, means for establishing a main circuit from said source through said rail, means for establishing an auxiliary circuit from said source through said rail, a detector unit, each of said circuits including a set of brushes engaging the rail, said unit being positioned between the brushes of each set, the brushes of one set being spaced closer to said unit than the brushes of the other set, means responsive to rail joints, and means whereby said rail-joint-responsive means renders one of said circuits effective and the other circuit inefiective.

16. In a detector mechanism adapted to travel along the rails of a track for detecting flaws therein, said rails having joints, a source of current, means for establishing a main circuit from said source through said rail, means for establishing an auxiliary circuit from said source through said rail, a detector unit, each of said circuits including a set of brushes engaging the rail, said unit being positioned between the brushes of each set, the brushes of said auxiliary circuit being spaced closer to said unit than the brushes of said main circuit, means normally maintaining said main circuit effective, means responsive to said rail joints, and means whereby said rail-joint-responsive means renders said main circuit ineffective and said auxiliary circuit effective.

1 In a detector mechanism adapted to travel along the rails of a track for detecting flaws therein, said rails having joints including angle bars, a source of current, means for establishing a main circuit from said source through said rail, means for establishing an auxiliary circuit from said source through said rail, a detector unit, each of said circuits including a set of brushes engaging the rail, said unit being positioned between the brushes of each set, the brushes of one set being spaced closer to said unit than the brushes of the other set, means adapted to engage said angle bars, and means whereby the engagement of said preceding means with said angle bars renders one of said circuits effective and the other circuit ineffective 18. In a detector mechanism adapted to travel along the rails of a track for detecting flaws therein, said-rails having joints including angle bars, a source of current, means for establishing a main circuit from said source through said rail, means for establishing an auxiliary circuit from said source through said rail, a detector unit, each of said circuits including a set of brushes engaging the rail, said unit being positioned between the brushes of each set, the brushes of said auxiliary circuit being spaced closer to said unit than the brushes of said main circuit, means adapted to engage said angle bars, and means whereby the engagement of said preceding means with said angle bars renders said main circuit ineffective and said auxiliary circuit effective.

19. In a detector mechanism adapted to travel along the rails of a track for detecting flaws therein, said rails having joints including angle bars, a source of current, means for establishing a main circuit from said source through said rail, means for establishing an auxiliary circuit from said source through said rail, a detector unit, said main circuit including a set of brushes engaging the rail, said unit being positioned between said brushes and closer to the rear brush than the front brush, said auxiliary circuit including said rear brush and an additional front brush positioned nearer to said unit than said first front brush, means adapted to engage said angle bars, and means whereby the engagement of said preceding means with said angle bars renders one of said circuits effective and the other circuit ineffetcive.

20. In a detector mechanism adapted to travel along the rails of a track for detecting flaws therein, said rails having joints including angle bars, a source of current, means for establishing a main circuit from said source through said rail, means for establishing an auxiliary circuit from said source through said rail, a detector unit, said main circuit including a set of brushes engaging the rail, said unit being positioned between said brushes and closer to the rear brush than the front brush, said auxiliary circuit including said rear brush and an additional front brush positioned nearer to said unit than said first front brush, means adapted to engage said angle bars, and means whereby the engagement of said preceding means with said angle bars renders said main circuit inefiective and said auxiliary circuit effective.

21. In a detector mechanism adapted to travel along the rails of a track for detecting flaws therein, said rails having joints including angle bars, a source of current, means for establishing a main circuit from said source through said rail, means for establishing an auxiliary circut from said source through said rail, a detector unit, each of said circuits including a set of brushes engaging the rail, said unit being positioned between the brushes of each set, the brushes of said auxiliary circuit being spaced closer to said unit than the brushes of said main circuit, means adapted to engage said angle bars, and means whereby the engagement of said preceding means with said angle bars renders said main circuit inefiective and said auxiliary circuit efiective, said means for engaging said angle bars being so formed as to engage each angle bar until the last of said brushes has passed the respective joint.

22. In a detector mechanism adapted to travel along the rails of a track for detecting flaws therein, said rails having joints including angle bars, a source of current, means for establishing a main circuit from said source through said rail, means for establishing an auxiliary circuit from said source through said rail, a detector unit, said main circuit including a set of brushes engaging the rail, said unit being positioned between said brushes and closer to the rear brush than the .bar until the last of said brushes has passed the respective joint.

HARCOURT C. DRAKE. 

